Nanostarch-enhanced 3D printability of carrageenan emulsion gel for high-fidelity and nutrition-fortified fish fat mimics

3D-printed fish analogues have gradually been produced as substitutes for real fish meat for the rising of personalized diet and food safety, as well as environmental concerns related to marine biodiversity and seafood supply. However, it is still a challenge of preparing shaped fish fat mimics based on precise structural and nutritional regulations of food 3D printing technology. In this study, nanostarch (NS) particles were used to enhance the printability of carrageenan (CG) emulsion gels with different oils. The rheological properties, printing ability, printing precision, moisture state, microstructure, and emulsion stability of NS/CG emulsion gels as printable food-ink were investigated at different NS concentration ratios (0–5 wt%). Compared with native starch (micron-sized granules), the addition of nanoscale NS led to decreases in viscosity and G’ of inks for easier extruding performance. Also, NS (especially 4 wt%) shaped fish fat mimics with smoother surfaces, better printing precision and expansion rate. It optimized the mimic formula with tightly bound water T2b which was similar to that of real fish tissue. When the NS and CG contents were used at 4% and 2% (4N2G), respectively, the printed fat mimics had the highest printing precision (94.33%) and the best emulsion stability (Turbiscan stability index <0.1). Furthermore, when DHA-rich fish oil was introduced into the 4N2G system compared with soybean oil, it showed not only similar printing performance but also better microstructural homogeneity with increased nutrition supplements.